Omnidirectional multilayer device for enhanced optical waveguiding

Abstract

A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.

What is claimed is:  
     
       1. A device comprising: 
       at least one dielectric inner core region in which electromagnetic radiation is confined; and  
       at least two outer regions comprising dielectric material surrounding the inner core region, each with a distinct refractive index, said outer regions confining electromagnetic radiation within said inner core region, wherein  
       the refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for all angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of said electromagnetic radiation, and  
       wherein during operation the outer regions guide the electromagnetic radiation within the dielectric inner core region.  
     
     
       2. The device of  claim 1 , wherein said inner core region comprises a low dielectric material. 
     
     
       3. The device of  claim 2 , wherein said inner core region comprises a gas. 
     
     
       4. The device of  claim 3 , wherein said inner core region comprises air. 
     
     
       5. The device of  claim 1 , wherein the outer regions comprise alternating layers of low and high dielectric materials. 
     
     
       6. The device of  claim 5 , wherein said low dielectric material comprises a polymer or a glass. 
     
     
       7. The device of  claim 5 , wherein said high dielectric material comprises germanium or tellurium. 
     
     
       8. The device of  claim 1 , wherein said device is utilized to guide electromagnetic radiation in a plurality of broadband region. 
     
     
       9. The device of  claim 8 , wherein the electromagnetic radiation in said broadband regions is single mode. 
     
     
       10. The device of  claim 8 , wherein the electromagnetic radiation in said broadband regions is multi-mode. 
     
     
       11. The device of  claim 1 , wherein said device comprises a circular cross section. 
     
     
       12. The device of  claim 1 , wherein said device comprises a rectangular cross section. 
     
     
       13. The device of  claim 1 , wherein said device comprises a triangular cross section. 
     
     
       14. The device of  claim 1 , wherein said device comprises a hexagonal cross section. 
     
     
       15. The device of  claim 1 , wherein said device is utilized to guide high power electromagnetic radiation. 
     
     
       16. The device of  claim 1 , wherein said device is utilized to guide high power electromagnetic radiation around bends. 
     
     
       17. The device of  claim 1 , wherein said device is utilized to guide electromagnetic radiation in at least one broadband region. 
     
     
       18. The device of  claim 1 , wherein said inner core region has dimensions on the order of the wavelength of said electromagnetic radiation. 
     
     
       19. The device of  claim 1 , wherein said inner core region has dimensions larger than the wavelength of said electromagnetic radiation. 
     
     
       20. The device of  claim 1 , wherein said device is utilized as a microcavity to confine electromagnetic radiation. 
     
     
       21. A microcavity comprising: 
       at least one inner core region in which light is confined; and  
       at least two outer regions surrounding the inner core region, each with a distinct refractive index, said outer regions confining light within said inner core region, wherein  
       the refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for all angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of said light.  
     
     
       22. A waveguide which exhibits omnidirectional reflection, comprising: 
       at least one dielectric inner core region in which light is confined; and  
       at least two outer regions comprising dielectric material surrounding the inner core region, each with a distinct refractive index, said outer regions confining light within said inner core region, wherein  
       the refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for all angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of said light, and  
       wherein during operation the outer regions guide the electromagnetic radiation within the dielectric inner core region.  
     
     
       23. An article comprising: 
       a dielectric inner core extending along an axis; and  
       multiple dielectric layers surrounding the inner core about the axis,  
       wherein the multiple dielectric layers define a refractive index variation that produce a range of frequencies for which there is omnidirectional reflection for electromagnetic radiation incident on the multiple dielectric layers from the dielectric inner core, the range of frequencies For which there is omnidirectional reflection being defined from above by an upper frequency ω l , corresponding to a photonic band edge for normally incident electromagnetic radiation and from below by a lower frequency ω l  corresponding to an intersection between a photonic band edge for TM electromagnetic radiation and a light line defined by the dielectric inner core.  
     
     
       24. The article of claims  23 , wherein the axis is a waveguide axis and the alternating layers surround the inner core region about the waveguide axis to guide the electromagnetic radiation along the waveguide axis. 
     
     
       25. The article of  claim 24 , wherein the article comprises a circular cross section with respect to the waveguide axis. 
     
     
       26. The article of  claim 24 , wherein the article comprises a rectangular cross section with respect to the waveguide axis. 
     
     
       27. The article of  claim 24 , wherein the article comprises a triangular cross section with respect to the waveguide axis. 
     
     
       28. The article of  claim 24 , wherein the article comprises a hexagonal cross section with respect to the waveguide axis. 
     
     
       29. The article of  claim 24 , wherein the article is utilized to guide high power electromagnetic radiation. 
     
     
       30. The article of  claim 24 , wherein the article is utilized to guide high power electromagnetic radiation around bends. 
     
     
       31. The article of  claim 23 , wherein the multiple dielectric layers comprises alternating layers of high-index and low-index dielectric materials. 
     
     
       32. The article of  claim 31 , wherein the refractive index of the dielectric inner core is the refractive indices of the high-index and low-index materials are n 1  and n 2 , respectively, the thicknesses of the high-index and low-index layers are h 1  and h 2 , respectively, and n 1 >n 2 >n 0 . 
     
     
       33. The article of  claim 32 , wherein the refractive indices and thicknesses cause ω h >ω l , where:                  ω   h     +         2      c           h   2          n   2       +       h   1          n   1                  cos     -   1            (     -              n   1     -     n   2           n   1     +     n   2                )           ,     
            ω   1     =         2      c           h   2              n   2   2     -     n   0   2           +     h            n   2   2     -     n   0   2                        cos     -   1            (                n   1   2              n   2   2     -     n   0   2           -       n   2   2              n   1   2     -     n   0   2                   n   1   2              n   2   2     -     n   0   2           +       n   2   2              n   1   2     -     n   0   2                    )       .                 (   6   )                         
     
     
       34. The article of  claim 33 , wherein the number of alternating layers is sufficient to cause the omnidirectional reflectivity to be greater than 95% for electromagnetic radiation incident on the alternating layers from the inner core at all angles ranging from 0° to 80° and all polarizations for all frequencies in the omnidirectional range of frequencies. 
     
     
       35. The article of  claim 23 , wherein said low dielectric material comprises a polymer or a glass. 
     
     
       36. The article of  claim 35 , wherein said high dielectric material comprises germanium or tellurium. 
     
     
       37. The article of  claim 23 , wherein said inner core region has dimensions larger than a wavelength of the electromagnetic radiation in the omnidirectional range of frequencies. 
     
     
       38. The article of  claim 23 , wherein said inner core region has dimensions on the order of a wavelength of the electromagnetic radiation in the omnidirectional range of frequencies. 
     
     
       39. The article of  claim 23 , wherein the refractive index variation produce a range to midrange ratio, defined as (ω h −ω l )/[1/2)(ω h +ω l )], that is greater than or equal to 10%. 
     
     
       40. The article of  claim 23 , wherein the refractive index variation produce a range to midrange ratio, defined as (ω h −ω l )/[(1/2)(ω h +ω l )], that is greater than or equal to 20%. 
     
     
       41. The article of  claim 23 , wherein the refractive index variation produce a range to midrange ratio, defined as (ω h −ω l )/[(1/2)(ω h +ω l )], that is greater than or equal to 30%. 
     
     
       42. The article of  claim 23 , wherein the refractive index variation produce a range to midrange ratio, defined as (ω h −ω l )/[(1/2)(ω h +ω l )], that is greater than or equal to 40%. 
     
     
       43. The article of  claim 23 , wherein said inner core region comprises a gas. 
     
     
       44. The article of  claim 23 , wherein the alternating layers complete surround the inner core to define a microcavity in which electromagnetic radiation is confined. 
     
     
       45. A waveguide comprising: 
       a dielectric inner core extending along a waveguide axis; and  
       alternating layers of high-index and low-index dielectric materials surrounding the inner core about the waveguide axis to guide electromagnetic radiation along the waveguide axis,  
       wherein the refractive index of the dielectric inner core is no, the refractive indices of the high-index and low-index materials are n 1  and n 2 , respectively, the thicknesses of the high-index and low-index layers are h 1  and h 2 , respectively, and n 1 >n 2 >n 0 , and  
       wherein the refractive indices and thicknesses cause ω h >ω 1 , where:                  ω   h     +         2      c           h   2          n   2       +       h   1          n   1                  cos     -   1            (     -              n   1     -     n   2           n   1     +     n   2                )           ,     
            ω   1     =         2      c           h   2              n   2   2     -     n   0   2           +     h            n   2   2     -     n   0   2                        cos     -   1            (                n   1   2              n   2   2     -     n   0   2           -       n   2   2              n   1   2     -     n   0   2                   n   1   2              n   2   2     -     n   0   2           +       n   2   2              n   1   2     -     n   0   2                    )       .                 (   6   )                         
     
     
       46. The waveguide of  claim 45 , wherein the refractive indices and the thicknesses produce a range to midrange ratio, defined as (ω h −ω l )/[(1/2)(ω h +ω 1 )], that is greater than or equal to 10%. 
     
     
       47. The waveguide of  claim 46 , wherein the range to midrange ratio is greater than or equal to 20%. 
     
     
       48. The waveguide of  claim 47 , wherein the range to midrange ratio is greater than or equal to 30%. 
     
     
       49. The waveguide of  claim 48 , wherein the range to midrange ratio is greater than or equal to 40%. 
     
     
       50. The waveguide of  claim 45 , wherein said inner core region has dimensions larger than a wavelength of the electromagnetic radiation in the omnidirectional range of frequencies. 
     
     
       51. The waveguide of  claim 45 , wherein the number of alternating layers is sufficient to cause the omnidirectional reflectivity to be greater than 95% for electromagnetic radiation incident on the alternating layers from the inner core at all angles ranging from 0° to 80° and all polarizations for all frequencies in the omnidirectional range of frequencies. 
     
     
       52. The waveguide of  claim 45 , wherein said inner core region comprises a gas. 
     
     
       53. The waveguide of  claim 45 , wherein said inner core region has dimensions on the order of a wavelength of the electromagnetic radiation in the omnidirectional range of frequencies.